In high pressure, high speed pumps used to supply hot liquid to wash manifolds in parts washers, the NPSH or net positive suction head requirements at the suction side or inlet of the pump limits the temperature to which the cleaning fluid can be heated. If the NPSH is reduced beyond the pump inlet limitations, the suction force at the inlet of the pump system will reduce the pressure to the vapor pressure of the heated liquid so that the heated liquid is converted to vapor.
Prior parts washers generally solve this problem by either lowering the temperature to which the cleaning fluid is heated or increasing the depth of the cleaning fluid to thereby meet the pump NPSH requirements. However, it is desirable to run the parts washer utilizing cleaning fluid that is at a temperature near its boiling temperature since higher temperature cleaning fluid is generally more effective in cleaning the parts to be washed. In addition, higher temperatures allow for longer rinse cycles due to increased evaporation, thus further enhancing the cleaning performance of the parts washer. Likewise, while desirable to run the parts washer with cleaning fluid at this high temperature, it is also desirable to maintain the fluid depth as low as possible to thereby reduce the height of the fluid holding space in the parts washer, and thus the height of the parts washer itself.